1. Field of the Invention
The present invention relates to an electric contact device for establishing electric contact with contactors or contact elements of other devices such as a semiconductor device. The present invention further relates to a semiconductor device test socket using the contact device, to a semiconductor module using the contact device, and to a method of testing a semiconductor device.
2. Background Art
Some semiconductor devices, such as semiconductor integrated circuits, use ball grid array (BGA) contactor system. The ball grid array contactor system is embodied by means of arranging a plurality of ball-type contactors on one surface of a package having a semiconductor chip encapsulated therein. Respective ball contactor is connected to corresponding electrodes of the semiconductor chip encapsulated in the package and act as external terminals.
A test socket is used at a time of testing of such a semiconductor device. Further, when a semiconductor device is mounted on a circuit board such as a printed board, a semiconductor module mounting a semiconductor device on a mount socket is used. An electric contact device for establishing electric contact with respective contactor of a semiconductor device is built into the test socket or the semiconductor module.
FIGS. 22 through 24 shows examples of conventional electric contact devices of such a type. The drawings illustrate a conventional contact mechanism to be brought into contact with a single ball contactor or contact element. As shown in FIG. 22, the contact mechanism is embodied by means of a ball contactor 1 being pinched between a pair of strip contact leads 2A and 2B. In the example shown in FIG. 23, the contact leads 2A and 2B are positioned at diametrically opposite ends of the contactor 1 so as to mutually oppose. In the example shown in FIG. 24, the contact leads 2A and 2B are positioned so as to become offset with reference to the diameter of the contactor 1, in order to prevent inadvertent and faulty contact, which would otherwise arise between the contact lead 2A of one ball contactor 1 and the contact lead 2B of an adjacent ball contactor 1.
Theoretically, the ball contactor 1 comes into point contact with the contact leads 2A and 2B. However, when the ball contactor 1 becomes deformed, the ball contactor 1 comes into plane contact with the contact leads 2A and 2B. In view of a reduction in contact resistance, plane contact is preferable, and in order to attain this the ball contactor 1 must be deformed. If the ball contactor 1 is brought into reliable contact with the contact lead without involvement of deformation, contact resistance increases. Bringing contact leads into reliable contact with a ball contactor is not compatible with reducing contact resistance. As things stand now, one of these must be sacrificed.
The present invention was attained in consideration of the present circumstances, and proposes a new electric contact device having an improved contact mechanism capable of bringing contact leads into reliable contact with a contactor over a larger contact area while reducing contact resistance.
The present invention also proposes a new semiconductor device test socket having an improved contact mechanism capable of bringing contact leads into reliable contact with a contactor over a larger contact area while reducing contact resistance.
The present invention also proposes a new semiconductor module having an improved contact mechanism capable of bringing contact leads into reliable contact with a contactor over a larger contact area while reducing contact resistance.
The present invention also proposes a new method of testing a semiconductor device by utilization of an improved contact mechanism capable of bringing contact leads into reliable contact with a contactor over a larger contact area while reducing contact resistance.
According to one aspect of the present invention, an electric contact device comprises a contact mechanism having a contact lead, a drive mechanism for the contact lead, and an electric circuit for supplying an electric potential required by the contact lead of the contact mechanism. The contact mechanism has a contact lead, and the contact lead has a support end and a movable end, and is formed from elastic conductive material so as to constitute a ring-shape section therebetween. The drive mechanism moves the movable end of the contact lead of the contact mechanism. Herein, the drive mechanism moves the movable end such that the annular section of the contact lead of the contact mechanism enters an expanded state and assumes a larger diameter; a contactor is inserted into the ring-shape section while the contact lead remains in an expanded state; and the contact lead comes into contact with the contactor while entering a contracted state such that the ring-shape section assumes a smaller diameter.
According to another aspect of the present invention, an electric contact device comprises a plurality of contact mechanisms which are spaced apart from each other and placed on a base plate, each contact mechanism having a contact lead, and the contact lead having a support end and a movable end and being formed from elastic conductive material so as to constitute a ring-shape section therebetween. A drive mechanism is provided for commonly moving the movable ends of the contact leads of the contact mechanisms; and an electric circuit is provided for supplying an electric potential required by the contact leads of the contact mechanisms. Herein, the drive mechanism moves the movable ends of the contact leads of the contact mechanisms such that the ring-shape sections enter an expanded state and assume a larger diameter; contactors are inserted into the respective ring-shape sections while the contact leads remain in an expanded state; and the contact leads come into contact with the contactors while entering a contracted state such that the ring-shape sections assume a smaller diameter.
According to another aspect of the present invention, an electric contact device comprises first and second contact mechanisms which are spaced apart from each other and placed on a base plate, each of the first and second contact mechanisms having a contact lead, and the contact lead having a support end and a movable end and being formed from elastic conductive material so as to constitute a ring-shape section therebetween.
A drive mechanism is provided for commonly moving the movable ends of the contact leads of the first and second contact mechanisms; and an electric circuit is provided for supplying an electric potential required by the contact leads of the first and second contact mechanisms. Herein, the drive mechanism moves the movable ends of the contact leads of the first and second contact mechanisms such that the ring-shape sections enter an expanded state and assume a larger diameter; contactors are inserted into the respective ring-shape sections while the contact leads remain in an expanded state; and the contact leads come into contact with the contactors while entering a contracted state in which the ring-shape sections assume a smaller diameter.
Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawings.